Fire control for filterhouse

ABSTRACT

A FIRE CONTROL SYSTEM FOR A BAG FILTERHOUSE WHICH AUTOMATICALLY PROJECTS A FIRE EXTINGUISHING SUBSTANCE ONTO A FIRE BURNING WITHIN THE FILTERHOUSE. THE FIRE CONTROL SYSTEM IS UNIQUELY ADAPTED TO UTILIZE AN EXISTING AIR JET SYSTEM OF BAG CLEANING THEREBY MAKING AVAILABLE AN EFFECTIVE FIRE CONTROL SYSTEM AT VERY MINOR ADDITIONAL EXPENSE OF SPACE AND MATERIALS.

March 9, 1971 D 1, WYROUGH 3,568,415

FIRE CONTROL FOR FILTERHOUSE Filed April 2,5. 1969 1 l Pm- INVEN'l'oR.al//c/ J /4/g//0ag United States Patent O 3,568,415 FIRE CONTROL FORFILTERHOUSE David J. Wyrough, Wellsville, N.Y., assignor to The AirPreheater Company, Inc., Wellsville, N.Y. Filed Apr. 25, 1969, Ser. No.819,289 Int. Cl. B01d 46/04 US. Cl. 55-302 4 Claims ABSTRACT OF THEDISCLOSURE A fire control system for a bag filterhouse whichautomatically projects a fire extinguishing substance onto a fireburning within the filterhouse. The fire control system is uniquelyadapted to utilize an existing air jet system of bag cleaning therebymaking available an effective fire control system at very minoradditional expense of space and materials.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION This inventiontherefore provides a fire extinguishing system for a bag filterhousewhere a fire extinguishing substance may be effectively presented to amultiplicity of locations where the burning of combustible filtrate hascommenced.

The invention utilizes the same equipment for the presentation of thefire extinguishing material that already is normally used for periodicbag cleaning, thus an effective fire control system is readily providedfor a bag filterhouse using an already existing air jet system ofcleaning.

BRIEF DESCRIPTION OF THE DRAWING The single figure of the drawing is across-sectional view of a bag type cleaning apparatus constructed inaccordance with the teachings of this invention.

THE SPECIFICATION In the drawing a housing has an inlet 12 for dustbearing gas and an outlet 14 for the exhaust of clean gas therefrom. Thehousing is separated into upper and lower portions by a tube sheet 16yhaving a series of ports 18 therein. The ports are surrounded by anannular collar 22 to which are clamped bag filters 24 of the customaryform. A skeletal cage or support 26 inside each bag filter preventsexcess pressure on the outside surface of the bag from causing the bagto collapse inwardly.

A series of nozzles 28 are connected to a manifold from which compressedair is exhausted into the open end of each filter bag 24. As thecompressed air is exhausted into the open end of each bag, the excesspressure thereof causes a momentary halt to the flow through the bagfilter of the air to be cleaned, the bag fiexes slightly outward, thedust cake on the outer surface thereof is broken loose and it falls to`the bottom of hopper 36 where it may be removed through door 38.

The valve 42 controlling the flow of air for cleaning the bags isintermittently controlled by the timer 44 connected to an electricalsource 46. Positioned in the electrical circuit intermediate the timer44 and the source of electrical energy 46 is a meltable fuse-valve 48controlling flow in the duct 52 leading to the manifold 32. A source offire extinguishing material, such as carbon tetrachloride, is connectedto the duct 52 under pressure whereby opening the fuse valve 48 willpermit the fire extinguishing material to flow to the duct 32 and thedependent nozzles 28 so that such fire extinguishing material will beexhausted into the open end of each bag 24.

Inasmuch as the dust cake collected on each bag frequently is extreme-lyfiammable, my invention provides an arrangement by which a fire of thecollected dust particles on the surface of the bags or in anotherportion of the lter chamber may be quickly smoothered by a blast of fireextinguishing material directed into the open end of each bag 24.

In accordance with my invention I provide a source of pressurized fireextinguishing ma-terial 52 connected to the supply duct or manifold 32leading to each nozzle 28. A meltable fuse-valve 48 located in the ductleading from the source 52 to the duct 32 is set to remain normallyclosed whereby the fire extinguishing material is normally excluded fromthe duct 32 and its connecting nozzles. Should a fire occur within thehousing, the temperature would rise somewhat and the fuse-valve wouldconsequently melt at a predetermined temperature. As the fuse-valve 48would melt, the source of electrical energy operating the timer 44 woudbe interrupted and the normally closed valve 42 would close to halt thefiow of air to the bag filters until such time as the apparatus could becompletely re-set.

As the fuse-valve 48 melts to open the passageway to the duct 32,pressurized fire extinguishing fluid would be exhausted from eachnozzle, and any fire in the filter bags would be quickly subjected tothe fire extinguishing fluid. Simultaneously, the source of air normallyused for bag cleaning would be cut off by closure of the valve 42.Although not illustrated in the drawing, a similar valve may be placedin the inlet duct 12 to be controlled by the same fuse 42 whereby itsmelting would permit the valve in duct 12 to close and completely closeoff the chamber within housing 10 to a source of air.

More rapid response to a rise of temperature in housing 10 may berealized if the fuse-valve 48 is located on the underside of the tubesheet 16 where the threat of potential burning is greatest and atemperature rise from burning material would be most quickly detected.This and various other changes may be made in the device withoutdeparting from the spirit of the invention. It is accordingly intendedthat all matter contained in the above description or shown in theaccompanying drawing shall be interpreted as illustrative and not in alimiting sense.

I claim:

1. A bag filter apparatus for filtering solids from a gas carriercomprising a filter housing enclosing a filter compartment having aninlet for gas to be filtered and an outlet for the exhaust of clean gastherefrom, a filter bag with an open end and a closed end arranged tolie intermediate the inlet and the outlet of the filter housing meanssupporting the filter bag at its open end for preventing by-pass of thefilter bag, cleaning means for the filter bag comprising a nozzlealigned with and directed towards the open end of the filter bag forexhausting cleaning gas therefrom into the open end of said filter bag,a source of cleaning gas, duct means connecting said `source to saidnozzle to supply cleaning gas thereto, valving means in said duet tocontrol the fiow of cleaning gas from the source to the nozzle, a sourceof fire extin- 3 guishing material, a conduit connecting the source ofre extinguishing material to the dust means, valving means in theconduit controlling the How of said material to the nozzle therethroughand means responsive to temperature within the lter housing tosimultaneously actuate the valving means in the duct for the cleaninggas and the Valving means controlling the supply of re eX- tinguishingmaterial through the conduit to terminate the ow of cleaning air to thenozzles and permit the flow of fire extinguishing material thereto upona predetermined increase in temperature.

2.y Apparatus for ltering solids from a uid carrier as dened in claim 1wherein the means responsive to temperatures of the filter compartmentcomprises a meltable fuse in the passageway intermediate the source ofire extinguishing material and the nozzle.

3. Apparatus for ltering solids from a uid carrier as defined in claim 1wherein the cleaning fluid and the re extinguishing material are bothcontained at their sources under pressure whereby opening theirrespective valving means permits them to exhaust from the nozzle intothe filter bag.

4. Apparatus for filtering solids from a uid carrier as defined in claim1 wherein the source of cleaning :duid and the source of reextinguishing material lie at opposite ends of a common passageway.

References Cited UNITED STATES PATENTS 7/1952 Rand et al. 169-19 4/ 1953Farr 55-242 OTHER REFERENCES Pulverizing Machinery Bulletin PC-l, pp.1-12, Apr- 25, 1966 (a copy in 55341).

FRANK W. LUTTER, Primary Examiner B. NOZICK, Assistant Examiner UJS. C1.X.R.

